Tie camera location/view to texture appearance?
It seems that you are looking for a channel which describes the angle of a surface with respect to the camera view. This is achieved by the Layer Weight and Fesnel nodes, found in the Input node category. The mixing can be controlled using the facing or IOR values of the Layer Weight and Fresnel nodes as well as a Color Ramp or Map Range node further tweaking/contrast. See the following node setup: